Patient lift apparatus

ABSTRACT

There is described a patient lift apparatus comprising a supporting frame, a boom portion connected to the supporting frame via a pivot joint (PJ 1 ) to allow the boom portion to pivot with respect to the supporting frame about a pivot axis (PA 1 ), and a boom actuator to mechanically assist pivotal movement of the boom portion with respect to the supporting frame. The boom portion is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member and adjustment of an effective length of the telescopic arm. The patient lift apparatus further comprises a centering system configured to center the inner member with respect to the outer member and suppress a clearance between the inner member and outer member. The centering system includes a first centering element mounted on the outer member and interposed between an inner side of the outer member and an outer periphery of the inner member, and a second centering element mounted on the inner member and guided inside the outer member. The first and second centering elements are configured to suppress the clearance between the outer member and inner member. The first centering element is configured as a bushing member mounted on a distal end portion of the outer member, a portion of which bushing member extends between the inner side of the outer member and the outer periphery of the inner member. The second centering element is configured as a guiding member mounted on a distal end portion of the inner member and guided inside the outer member.

TECHNICAL FIELD

The present invention generally relates to a patient lift apparatus employed for lifting and transferring patients, which apparatus is especially intended to be used in the health care industry. The patient lift apparatus of the invention is in particular intended to be used for providing safe and comfortable assisted transfers for those patients with limited mobility or rehabilitation needs, especially for the purpose of transferring such patients from a seated position to a standing position, and vice versa. In that respect, the patient lift apparatus of the invention may also be referred to as a stand assist hoist or lifter.

BACKGROUND OF THE INVENTION

Patient lift apparatuses are already known in the art and available on the market. Examples thereof include for instance Invacare®'s Reliant™ 350 and Roze stand assist products.

International (PCT) Publication No. WO 2010/017438 A2 discloses a patient lift apparatus as embodied in the form of Invacare®'s aforementioned Roze product. This known patient lift apparatus comprises a supporting frame, a boom portion connected to the supporting frame via a pivot joint to allow the boom portion to pivot with respect to the supporting frame about a pivot axis, and a boom actuator to mechanically assist pivotal movement of the boom portion with respect to the supporting frame. A distal end of the boom portion is configured to include hook portions configured to allow attachment of a sling for holding and supporting a patient during lifting and transfer. Handle portions are furthermore provided on the boom portions to provide the patient with the option of a manual grip helping stabilization during patient lifting and transfer. This patient lift apparatus further comprises a leg/knee support (or “leg/knee pad”) and a foot support (or “foot plate”), both connected to the supporting frame. According to WO 2010/017438 A2, the leg/knee support is configured to be adjustable in height to adjust the position thereof to different needs and patient morphologies. More precisely, the leg/knee support is mounted on a vertical guide and rail mechanism configured to allow positioning of the leg/knee support at any desired vertical position.

According to WO 2010/017438 A2, the length of the boom portion is fixed and not adjustable. Patient lift apparatuses of the type comprising a length-adjustable boom portion are however known in the art.

U.S. Pat. No. 5,758,371 A for instance discloses a patient lift apparatus where the boom portion is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member and adjustment of an effective length of the telescopic arm.

US Patent Publication No. US 2011/0016628 A1 similarly discloses a patient lift apparatus of the type comprising a boom portion that is configured as a telescopic arm. In this particular instance, a simple pin-and-hole arrangement is provided to allow adjustment of the inner member of the telescopic arm at any desired one of a plurality of predefined longitudinal positions with respect to the outer member.

European Patent Publication No. EP 2 524 682 A1 discloses yet another example of a patient lift apparatus of the type comprising a boom portion that is configured as a telescopic arm.

U.S. Pat. No. 2,846,091 A discloses an invalid handing apparatus for vehicles of the type likewise comprising a boom portion that is configured as a telescopic arm. According to U.S. Pat. No. 2,846,091 A, lining of bearing material is interposed between inner and outer members of the telescopic arm.

U.S. Pat. No. 5,459,841 A discloses an invalid lift and transport apparatus of the type comprising a boom portion that is configured as a telescopic arm. In this case, the boom portion consists of a hydraulically actuated piston that is guided and adapted to slide inside a barrel portion under the action of a hydraulic pump.

German Utility Model No, DE 200 14 830 U1 likewise discloses a lift apparatus for physically disabled persons of the type comprising a boom portion that is configured as a telescopic arm. This document is silent with regard to the provision of any centering system configured to center the inner member of the telescopic arm with respect to the outer member of the telescopic arm and reduce or suppress clearance between the inner and outer members.

Japanese Patent Publication No. JP S53-35248 A discloses a support mechanism for a telescopic boom, which support mechanism includes first and second bearing elements designed to counteract load as applied at a distal end of the telescopic arm. This support mechanism is not designed or meant to act as a centering system.

The solutions disclosed in U.S. Pat. No. 5,758,371 A, US 2011/0016628 A1, EP 2 524 682 A1 and DE 200 14 830 U1 are useful in allowing adjustment of the patient lift apparatus to the actual size of each patient and to adjust the lifting amplitude to match the relevant need. Such solutions are not however entirely satisfactory from the point of view of the adjustability of the effective length of the boom portion. Furthermore, the necessary clearance, or play, between the inner and outer members of the telescopic arm may be to the detriment of comfort for the patient as the inner member may move under load within the space provided inside the outer member, leading to undesired and unpleasant movement for the patient during lifting and/or transfer.

The solution disclosed in U.S. Pat. No. 2,846,091 A is not satisfactory in that the lining of bearing material will inevitably deteriorate over time due to wear and excessive friction between the inner and outer members of the telescopic arm.

The solution disclosed in U.S. Pat. No. 5,459,841 A is not satisfactory in that it requires a relatively complex hydraulic actuation system to allow actuation of the telescopic arm.

U.S. Pat. Nos. 5,076,448 A and 5,897,101 A disclose hydraulic hoists or cranes of the type used in automotive maintenance and repair, which hydraulic hoists or cranes are not suitable for handling patients.

International (PCT) Publication No. WO 95/18592 A1 discloses a patient lift apparatus similar to that of WO 2010/017438 A2 where the leg/knee support is additionally configured to be releasable from the supporting frame. In this particular instance, the leg/knee support can be adjusted in height and potentially be released by actuating a simple thumbscrew.

According to WO 2010/017438 A2, the guide and rail mechanism includes a guide portion that forms an integral part of the supporting frame and of the locking/unlocking arrangement used to secure the leg/knee support to the supporting frame. More specifically, the guide portion is affixed to an accessory frame portion, or support mount, extending from the supporting frame, and the leg/knee support can be selectively released from the supporting mount by means of release handle provided on the guide portion. The leg/knee support of WO 2010/017438 A2 merely comprises a rail portion that is slidably guided inside the guide portion and selectively lockable in position by means of the locking/unlocking arrangement. Furthermore, the leg/knee support of WO 2010/017438 A2 includes a handle, but this handle has no particular locking or unlocking function. As simpler, better integrated solution is therefore desirable.

International (PCT) Publication No. WO 96/11658 A1 discloses a patient lift apparatus where the leg/knee support is adapted to pivot about a pivot axis and thereby follow movement of the patient's legs/knees upon standing or sitting.

Dutch Patent No. NL 1012559 C2 similarly discloses a patient lift apparatus comprising a leg/knee support that can be pivoted about a pivot axis. In this particular instance, electric motors are provided to cause pivotal movement of the leg/knee support.

The aforementioned known solutions are not fully satisfactory, and there remains a need for an improved solution.

SUMMARY OF THE INVENTION

A general aim of the invention is to provide an improved patient lift apparatus.

More specifically, an aim of the present invention is to provide such a patient lift apparatus of the type comprising a boom portion configured as a telescopic arm, which patient lift apparatus does not suffer from the shortcomings of the above-mentioned known solutions.

Yet another aim of the invention is to provide such a solution which can compensate for the necessary presence of a clearance between the inner and outer members of the telescopic arm and thereby improve comfort for the patient.

A further aim of the invention is to provide such a solution where the effective length of the telescopic arm can easily be adjusted, without this compromising the patient's or caregiver's safety or being to the detriment of patient's comfort.

Still another aim of the invention is to provide such a solution that is particularly suited to act as stand assist hoist for the purpose of transferring patients from a seated position to a standing position, and vice versa, with improved adjustability to the patient's needs and morphology and providing better comfort for the patient during assisted transfer.

These aims are achieved thanks to the solutions defined in the claims.

In accordance with a first aspect of the invention, there is provided a patient lift apparatus according to claim 1, namely a patient lift apparatus comprising a supporting frame, a boom portion connected to the supporting frame via a pivot joint to allow the boom portion to pivot with respect to the supporting frame about a pivot axis, and a boom actuator to mechanically assist pivotal movement of the boom portion with respect to the supporting frame. The boom portion is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member and adjustment of an effective length of the telescopic arm. According to this first aspect of the invention, the patient lift apparatus further comprises a centering system configured to center the inner member with respect to the outer member and suppress a clearance between the inner member and outer member.

According to the invention, the centering system includes:

-   -   a first centering element mounted on the outer member and         interposed between an inner side of the outer member and an         outer periphery of the inner member; and     -   a second centering element mounted on the inner member and         guided inside the outer member,

the first and second centering elements being configured to suppress the clearance between the outer member and the inner member.

Furthermore, the first centering element is configured as a bushing member mounted on a distal end portion of the outer member, a portion of which bushing member extends between the inner side of the outer member and the outer periphery of the inner member, and the second centering element may be configured as a guiding member mounted on a distal end portion of the inner member and guided inside the outer member. In this latter context, the bushing member may comprise a plurality of extensions extending longitudinally between the inner side of the outer member and the outer periphery of the inner member and a plurality of flat spring elements located on said extensions. In that respect, the flat spring elements are preferably interposed between the inner side of the outer member and said extensions to press the said extensions inwardly towards the outer periphery of the inner member.

By way of preference, the patient lift apparatus further comprises an indexing mechanism configured to allow positioning of the inner member at a plurality of predefined longitudinal positions with respect to the outer member. This indexing mechanism may in particular comprise a releasable indexing plunger mounted on the outer member and having a retractable end portion configured to engage with any selected positioning hole among a plurality of positioning holes distributed longitudinally along a portion of the inner member. In this latter context, the centering system can especially be mounted on the outer member and inner member and be configured such as not to interfere with operation of the releasable indexing plunger.

In accordance with a particularly preferred embodiment, the indexing mechanism further comprises a manually-operable release lever that is mechanically linked to the releasable indexing plunger to selectively allow retraction of the retractable end portion of the indexing plunger out of engagement with the selected positioning hole, thereby releasing the inner member and allowing repositioning of the inner member with respect to the outer member at a different one of the predefined longitudinal positions.

By way of preference, one end of the manually-operable release lever may be coupled to the releasable indexing plunger and an intermediate portion of the manually-operable release lever may be configured to act as a pivot about which the manually-operable release lever can pivot upon being manually operated to cause retraction of the retractable end portion of the indexing plunger.

These latter features can advantageously be implemented independently of the aforementioned centering system. In that respect, in accordance with another aspect of the invention, there is provided a patient lift apparatus according to claim 9, namely a patient lift apparatus comprising a supporting frame, a boom portion connected to the supporting frame via a pivot joint to allow the boom portion to pivot with respect to the supporting frame about a pivot axis, and a boom actuator to mechanically assist pivotal movement of the boom portion with respect to the supporting frame. The boom portion is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member and adjustment of an effective length of the telescopic arm. According to this other aspect of the invention, the patient lift apparatus further comprises an indexing mechanism configured to allow positioning of the inner member at a plurality of predefined longitudinal positions with respect to the outer member, which indexing mechanism comprises:

-   -   a releasable indexing plunger mounted on the outer member and         having a retractable end portion configured to engage with any         selected positioning hole among a plurality of positioning holes         distributed longitudinally along a portion of the inner member;         and     -   a manually-operable release lever that is mechanically linked to         the releasable indexing plunger to selectively allow retraction         of the retractable end portion of the indexing plunger out of         engagement with the selected positioning hole, thereby releasing         the inner member and allowing repositioning of the inner member         with respect to the outer member at a different one of the         predefined longitudinal positions.

Furthermore, according to this other aspect of the invention, one end of the manually-operable release lever is coupled to the releasable indexing plunger and an intermediate portion of the manually-operable release lever may be configured to act as a pivot about which the manually-operable release lever can pivot upon being manually operated to cause retraction of the retractable end portion of the indexing plunger.

The indexing mechanism may advantageously be located on a lower portion of the outer member, and the aforementioned manually-operable release lever may especially be supported onto a same mounting bracket as one end of the boom actuator. Furthermore, a cover element may be located on the mounting bracket, covering part of the indexing mechanism, to prevent finger or hand entrapment.

According to a further embodiment of the invention, the releasable indexing plunger is preferably a spring-loaded indexing plunger whose retractable end portion is configured to be urged towards an inner side of the outer member and to automatically engage with any one of the plurality of positioning holes provided on the inner member upon alignment therewith.

Lastly, the patient lift apparatus of the invention may further comprise a leg/knee support connected to the supporting frame. This leg/knee support is preferably configured to be selectively releasable from the supporting frame, and in particular comprises a manually-operable release mechanism to selectively release the leg/knee support from the supporting frame. Alternatively, or additionally, the leg/knee support is preferably configured to be partly pivotable with respect to the supporting frame about an axis of rotation and within a defined pivoting range.

Further advantageous embodiments of the invention are discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will appear more clearly from reading the following detailed description of embodiments of the invention which are presented solely by way of non-restrictive examples and illustrated by the attached drawings in which:

FIG. 1 is a perspective view of a patient lift apparatus, or stand assist hoist, in accordance with a preferred embodiment of the invention;

FIG. 2 is a side view of the patient lift apparatus of FIG. 1 showing a boom portion thereof that is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member;

FIG. 2A is a partial side view of the patient lift apparatus of FIG. 1 showing the boom portion pivoted to a lower position compared to that shown in FIG. 2;

FIG. 2B is an enlarged partial perspective view of the patient lift apparatus of FIG. 1 showing a leg/knee support as mounted on a supporting frame of the patient lift apparatus;

FIG. 2C is an enlarged partial perspective view of a support mount provided on the supporting frame, namely at a distal end of a mast extension, for connection of the leg/knee support of FIG. 2B;

FIG. 3A is an enlarged partial side view of a cross-section of the telescopic arm of the patient lift apparatus of FIG. 1 showing an indexing mechanism configured to allow positioning of the inner member at a plurality of predefined longitudinal positions with respect to the outer member, the indexing mechanism being shown in a state where it engages with the telescopic arm;

FIG. 3B is an enlarged partial side view of the same cross-section of the telescopic arm as depicted in FIG. 3A, the indexing mechanism being shown in a state where it is disengaged from the telescopic arm to allow the inner member to be displaced with respect to the outer member;

FIG. 4A is an enlarged partial perspective view of a section of the telescopic arm of the patient lift apparatus of FIG. 1 showing a centering system configured to center the inner member with respect to the outer member and suppress a clearance between the inner member and outer member;

FIG. 4B is an enlarged partial perspective view of the centering system of FIG. 4A, with the outer member being omitted for the purpose of illustration;

FIG. 5 is an enlarged side view of a cross-section of the leg/knee support as used in connection with the patient lift apparatus of FIG. 1, which leg/knee support is advantageously configured to be selectively releasable from the supporting frame of the patient lift apparatus as well as to be partly pivotable with respect to the supporting frame about a pivot axis and within a defined pivoting range; and

FIGS. 6A and 6B are partial side views of a cross-section of the leg/knee support of FIG. 5, as connected to the supporting frame, illustrating the leg/knee support in two extreme, tilted positions.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will be described in relation to various illustrative embodiments. It shall be understood that the scope of the invention encompasses all combinations and sub-combinations of the features of the embodiments disclosed herein.

As described herein, when two or more parts or components are described as being connected, secured or coupled to one another, they can be so connected, secured or coupled directly to each other or through one or more intermediary parts.

The invention will be described in relation to various embodiments of a patient lift apparatus, as depicted in FIGS. 1 to 6A-B. The patient lift apparatus shown in FIGS. 1 and 2 is generally designated by reference numeral 1 and is especially designed to act as stand-assist hoist for the purpose of transferring patients from a seated position to a standing position, and vice versa.

Referring to FIGS. 1 and 2, there is shown a perspective view and a side view, respectively, of the patient lift apparatus 1, which includes a supporting frame 10 comprising a base member 11, a mast 12 and a pair of supporting legs 13 provided at their ends with casters 14. An opening angle of the supporting legs 13 is advantageously adjustable by means of an adjustment device located on a rear end of the patient lift apparatus 1, as is known in the art. A suitable steering handle 16 is provided on the mast 12 to allow a caregiver to move and position the apparatus 1 according to the needs.

A boom portion 18 is connected to the supporting frame 10, namely to mast 12, via a pivot joint PJ1 thereby allowing the boom portion 18 to pivot with respect to the mast 12 about a pivot axis PA1. Pivot axis PA1 is understood to extend essentially parallel to a horizontal plane in the illustrated example. A boom actuator 15 is further provided to mechanically assist pivotal movement of the boom portion 18 with respect to the mast 12, which boom actuator 15 is mounted, at a lower end, on a mast extension 12A extending away from the mast 12. An upper end of the boom actuator 15, designated by reference sign 15A, is connected to the boom portion 18, namely via a mounting bracket 185 located on a lower portion of the boom portion 18. The boom actuator 15 can for instance be an electrically driven screw-type, hydraulic or pneumatic actuator, as is known in the art.

At a distal end of the boom portion 18, the boom portion 18 is here configured to exhibit a pair of arms, forming an integral part of the boom portion 18, each arm comprising a handle portion 20 shaped to provide a manual grip for the patient. Also provided on each arm is at least one hook portion 25 for attachment of a sling (not shown).

In the illustrated example, the boom portion 18 is configured as a telescopic arm 180 comprising (see especially FIGS. 2 and 2A) an outer member 181 and an inner member 182 that is telescopically received inside the outer member 181 to allow displacement of the inner member 182 with respect to the outer member 181 and adjustment of an effective length of the telescopic arm 180, as schematically illustrated by the double arrow in FIG. 2 (see also FIG. 2A).

In accordance with a first aspect of the invention, as for instance illustrated by FIGS. 4A-B, the patient lift apparatus 1 further comprises a centering system, which centering system is configured to center the inner member 182 with respect to the outer member 181 and suppress a clearance between the inner member 182 and the outer member 181. A particularly advantageous embodiment of this centering system is shown in FIGS. 4A-B (see also FIGS. 3A-B), and generally designated by reference numeral 300, which centering system 300 will be described in greater detail hereafter.

In accordance with another aspect of the invention, which other aspect is advantageously combinable with the aforementioned first aspect of the invention, the patient lift apparatus 1 further comprises an indexing mechanism configured to allow positioning of the inner member 182 at a plurality of predefined longitudinal positions with respect to the outer member 181. A particularly advantageous embodiment of this indexing system is shown in FIGS. 3A-B, as well as partly visible in FIGS. 1, 2 and 2A, and generally designated by reference numeral 200, which indexing mechanism 200 will be described in greater detail hereafter.

Also visible in FIGS. 1 and 2 is a leg/knee support (or “leg/knee pad”) 50 connected to the supporting frame 10, which leg/knee support 50 is shaped and advantageously padded to provide support for the patient's legs or knees during transfer of the patient from a seated position to a standing position, and vice versa. The leg/knee support 50 is also shown in greater detail on FIG. 2B, reference sign 500A designating two support surfaces extending laterally for supporting the patient's legs/knees. The leg/knee support 50 is connected to the supporting frame 10, namely to the mast 12, via the aforementioned mast extension 12A. Also shown in FIGS. 1 and 2 is an optional foot support (or “foot plate”) 60, which foot support 60 is configured to receive the patient's feet. In accordance with a preferred embodiment of the invention, the leg/knee support 50 may be configured to be selectively releasable from the supporting frame 10. The foot support 60 may likewise be configured to be selectively releasable from the supporting frame 10.

A support mount 120 is provided on the supporting frame 10, namely at a distal end of the mast extension 12A, to secure the leg/knee support 50 onto the supporting frame. Part of this support mount 120 is visible on FIG. 2 and FIG. 2B. In the illustrated embodiment, upon being released, the leg/knee support 50 can be removed from the support mount 120 by sliding the leg/knee support 50 upward along the support mount 120, the support mount 120 acting as a guide. FIG. 2C illustrates the support mount 120, without the leg/knee support 50 connected thereto.

FIG. 3A is an enlarged partial side view of a cross-section of the telescopic arm 180 of the patient lift apparatus 1 of FIG. 1 showing a particularly preferred embodiment of the indexing mechanism 200. In accordance with this preferred embodiment, the indexing mechanism 200 comprises a releasable indexing plunger 210 mounted on the outer member 181 and having a retractable end portion 210A configured to engage with any selected positioning hole among a plurality of positioning holes 182A that are distributed longitudinally along a portion of the inner member 182. FIG. 3A shows the retractable end portion 210A engaged with the second positioning hole 182A provided on the inner member 182 starting from the right. Eight positioning holes 182A are visible in FIG. 3A, but it should be appreciated that any number of positioning holes 182A could be provided. The actual number of positioning holes 182A, and the distribution thereof along the length of the inner member 182, will be determined according to the needs, especially the desired overall amplitude of adjustment of the effective length of the telescopic arm 180 and the amplitude of each individual adjustment step.

As illustrated, the indexing mechanism 200 further comprises a manually-operable release lever 250 that is mechanically linked to the releasable indexing plunger 210 to selectively allow retraction of the retractable end portion 210A of the indexing plunger 210 out of engagement with the selected positioning hole 182A, thereby releasing the inner member 182 and allowing repositioning thereof with respect to the outer member 181 at a different one of the predefined longitudinal positions. FIG. 3B shows the retractable end portion 210A retracted out of engagement from the positioning hole 182A. In the illustrated embodiment, one end 250A of the manually-operable release lever 250 is coupled to the releasable indexing plunger 210 and an intermediate portion of the manually-operable release lever 250 is configured to act as a pivot 250B about which the manually-operable lever 250 can pivot, upon being manually operated, as illustrated by FIGS. 3A-B, to cause retraction of the retractable end portion 210A of the indexing plunger 210. The relevant pivot axis of the manually-operable lever 250 is shown in FIGS. 3A-B and designated by reference sign PA2.

By way of preference, the indexing mechanism 200 is located on a lower portion of the outer member 181. In that respect, in the illustrated embodiment, the release lever 250 is pivotably supported onto the same mounting bracket 185 as the upper end 15A of the boom actuator 15, which leads to a particularly simple and elegant integration of the indexing mechanism 200. In that context, it is advantageous, for safety purposes, to additionally provide a cover element 280 located on the mounting bracket 185, as shown in FIGS. 3A-B (see also FIG. 1), to cover part of the indexing mechanism 200, namely the indexing plunger 210 and the end 250A of the release lever 250, and thereby prevent finger or hand entrapment.

The releasable indexing plunger 210 is preferably a spring-loaded indexing plunger whose retractable end portion 210A is configured to be urged towards an inner side of the outer member 181 and to automatically engage with any one of the plurality of positioning holes 182A provided on the inner member 182 upon alignment therewith.

In the illustrated example, disengagement of the retractable end portion 210A of the releasable indexing plunger 210 is caused by a slight pivoting movement of the release lever 250 about the pivot axis PA2, namely in a counter-clockwise direction in the illustration of FIGS. 3A-B (as schematically illustrated by the curved arrow), i.e. by pressing the free end of the release lever 250 upward towards the outer member 181.

FIG. 4A is an enlarged partial perspective view of a section of the telescopic arm 180 of the patient lift apparatus 1 of FIG. 1 showing a particularly preferred embodiment of the centering system 300. This centering system 300 is also visible in FIGS. 3A-B. Part of the outer member 181 has been omitted in the illustration of FIG. 4A for the purpose of explanation. According to this particularly preferred embodiment, the centering system 300 includes a first centering element, designated by reference numeral 310, mounted on the outer member 181 and interposed between an inner side 181A of the outer member 181 and an outer periphery 182B of the inner member 182. The centering system 300 further comprises a second centering element, designated by reference numeral 320, mounted on the inner member 182 and guided inside the outer member 181. In the illustrated embodiment, the first and second centering elements 310, 320 are configured to suppress the clearance between the outer member 181 and the inner member 182. The provision of the first and second centering elements 310, 320 is advantageous in that the centering elements 310, 320 can be designed to have better dimensional tolerances than that of the inner and outer member 181, 182, thereby eliminating play in the telescopic arm 180.

According to the invention, the first centering element is configured as a bushing member 310 mounted on a distal end portion of the outer member 181. A portion 310A, 310B of this bushing member 310 extends between the inner side 181A of the outer member 181 and the outer periphery 182B of the inner member 182, as this is visible in FIG. 4A. FIG. 4B shows the bushing member 310 with the outer member 181 being entirely omitted for the purpose of explanation. The second centering element is configured as a guiding member 320 mounted on a distal end portion of the inner member 182 and guided inside the outer member 181, as likewise shown in FIG. 4A. Guide surfaces 320A are provided on the periphery of the guide member 320 for guidance against the inner side 181A of the outer member 181.

Preferably, the bushing member 310 comprises a plurality of extensions 310A extending longitudinally between the inner side 181A of the outer member 181 and the outer periphery 182B of the inner member 182 and a plurality of flat spring elements 315 located on said extensions 310A. A total of eight such extensions 310A and flat spring elements 315 are provided in the illustrated example, disposed in pairs along each of four sides, but it should be appreciated that any number of extensions and spring elements, and geometry, could be contemplated. In the illustrated example, the flat spring elements 315 are interposed between the inner side 181A of the outer member 181 and the extensions 310A to press these extensions 310A inwardly towards the outer periphery of the inner member 182 (see also FIGS. 3A-B), thereby suppressing any play between the outer and inner members 181, 182.

Reference sign 310B in FIGS. 4A-B designates a further extension provided on each lateral side of the bushing member 310 to secure the bushing member 310 to the distal end of the outer member 181. This extension 310B is provided with a locking tab designed to engage with a corresponding mounting aperture provided on the outer member 181 (which mounting aperture is visible on FIGS. 1, 2 and 2A).

By way of preference, the centering system 300, which is mounted on the outer member 181 and the inner member 182, is configured such as not to interfere with operation of the releasable indexing plunger 210 of the aforementioned indexing mechanism 200.

The aforementioned solution to suppress the clearance between the outer and inner members 181, 182 of the telescopic arm 180 is particularly simple and robust. Other solutions, not presently claimed, could however be contemplated to reduce or suppress the clearance between the outer and inner members 181, 182, including solutions making use of e.g. an adjustable mechanism or an articulated linkage mounted on the inner member 182 and configured to translate a longitudinal displacement of a movable adjustment member into a radial displacement of two or more centering elements cooperating with the inner side 181A of the outer member 181. Similarly, centering of the inner member 182 with respect to the outer member 181 could also be performed by means of a radially-adjustable mandrel device mounted within the inner member 182 and projecting through the inner member 182 toward the inner side 181A of the outer member 181.

Turning now to FIGS. 5 and 6A-B, there is shown a particularly preferred embodiment of the leg/knee support 50. As this has already been mentioned, the leg/knee support 50 is preferably configured to be selectively releasable from the supporting frame 10. In accordance with an embodiment of the invention, as illustrated in FIG. 5, the leg/knee support 50 in particular comprises a manually-operable release mechanism to selectively release the leg/knee support 50 from the supporting frame 10. This manually-operable release mechanism comprises a retaining device 51 configured to cooperate with the support mount 120 provided on the supporting frame 10, namely at a distal end of the mast extension 12A, as again illustrated in FIGS. 6A-B. The manually-operable release mechanism further comprises a manually-operable handle 55 that cooperates with the retaining device 51 to allow selective release of the retaining device 51 from the support mount 120 and thereby allow removal of the leg/knee support 50 from the supporting frame 10.

As illustrated in FIG. 5, the retaining device 51 may in particular comprise first and second retaining members 51A, 51B forming a spacing therebetween and which are configured to act as a guide dimensioned to receive the support mount 120 (see also FIGS. 2C and 6A-B). More specifically, the first and second retaining members 51A, 51B are designed in such a way that the leg/knee support 50 can be slid onto the support mount 120, engagement and disengagement of the leg/knee support 50 occurring along a substantially vertical direction.

By way of preference, the manually-operable handle 55 is configured as a sliding handle provided on top of the leg/knee support 50, the handle 55 being guided by and allowed to translate within an upper portion of an outer casing 500 of the leg/knee support 50.

Translation of the movement of the manually-operable handle 55 into a release action of the retaining device 51 (as will be explained hereafter) can be carried out in different ways. One solution may consist in connecting the handle directly to the relevant retaining device or via an articulated linkage. A particularly simple and robust solution may consist, as illustrated in FIG. 5, in coupling the handle 55 to the retaining device 51 via a cable 52. In FIG. 5, reference sign 52A designates guide elements guiding the cable 52 from the handle 55 to the retaining device 51. This solution is particularly simple and provides great freedom for translating the movement of the handle 55 into the required release action of the retaining device 51. In the illustrated example, it will be appreciated that movement of the handle 55 and the release action of the retaining device 51 both occur as translational movements, however along different directions.

In a manner similar to the aforementioned indexing mechanism 200, the retaining device 51 comprises a releasable indexing plunger 510 having a retractable end portion 510A configured to engage with at least one positioning hole 120A provided on the support mount 120. In the illustrated embodiment, the releasable indexing plunger 510 is mounted on the first retaining member 51A and the retractable end portion 510A extends through the spacing formed between the first and second retaining members 51A, 51B towards the second retaining member 51B. In this particular instance, the releasable indexing plunger 510 is mechanically coupled to an end of the cable 52 to cause retraction of the retractable end portion 510 upon actuation of the handle 55.

Only one position hole 120A could be provided for the purpose of securing the leg/knee support 50 to the support mount 120. By way of preference, a plurality of positioning holes 120A are distributed along a portion of the support mount 120 to allow a vertical adjustment of the leg/knee support 50 with respect to the supporting frame 10, as this is visible in FIGS. 2B-C and 6A-B. In that respect, the retractable end portion 510A of the releasable indexing plunger 510 is likewise configured to engage with any selected positioning hole among the plurality of positioning holes 120A to allow adjustment of a vertical position of the leg/knee support 50 with respect to the supporting frame 10.

Like the releasable indexing plunger 210, the releasable indexing plunger 510 is preferably a spring-loaded indexing plunger whose retractable end portion 510A is configured to be urged towards the support mount 120 and to automatically engage with any one of the positioning holes 120A provided on the support mount 120 upon alignment therewith.

It will be appreciated that the aforementioned manually-operable release mechanism provides a simple and robust solution ensuring that the leg/knee support 50 is adequately secured to the supporting frame 10, while allowing easy and quick removal of the leg/knee support 50, without this requiring any tool.

In accordance with another embodiment of the invention, the leg/knee support 50 is configured to be partly pivotable with respect to the support mount 120 about a pivot axis, identified in FIGS. 5 and 6A-B by reference sign PA3, and within a defined pivoting range. More specifically, the outer casing 500 is configured to be pivotable with respect to the retaining device 51 about the pivot axis PA3 and within said defined pivoting range.

In accordance with this embodiment of the invention, at least one spring element 511, 512 coupling the outer casing 500 to the retaining device 51 is provided, which at least one spring element 511, 512 is configured to bring the outer casing 500 to a default position with respect to the retaining device 51 when no external force is applied onto the outer casing 500. By way of preference, as illustrated in FIG. 5, a pair of spring elements 511, 512 is provided, which pair of spring elements 511, 512 is configured to bring the outer casing 500 to the default position, which default position is a median position between two extreme tilted positions. Such two extreme tilted positions are illustrated in FIG. 6A and FIG. 6B.

More specifically, in the illustrated embodiment, each spring element 511, 512 is a tension spring, namely a spring that stretches as load is applied to it. One end of each spring element 511, 512 is attached to a corresponding location of the retaining device 51 and the other end of each spring element 511, 512 is attached to a corresponding spring mount 501, respectively 502, provided on the outer casing 500. As show in FIG. 5, the first and second spring elements 511, 512 are disposed essentially symmetrically about the pivot axis PA3, meaning that one or the other spring element 511, 512 will stretch as the outer casing 500 pivots about the pivot axis PA3.

Referring to FIG. 6A, which shows the leg/knee support 50 in a first extreme tilted position where the outer casing 500 is pivoted in the clockwise direction about pivot axis PA3, pivotal movement of the outer casing 500 causes an extension of the second (lower) spring element 512 compared to the default position illustrated in FIG. 5. By contrast, the first (upper) spring element 511 is relieved from any tension. In this first extreme tilted position the first (upper) spring mount 501 comes in abutment with a corresponding section of the retaining device 51, preventing further pivotal movement of the outer casing 500 in the clockwise direction. When the external force applied on the outer casing 500 is suppressed (namely when the contact with the patient's legs or knees is interrupted), the second spring element 512 will automatically pull the outer casing 500 to pivot in the counter-clockwise direction and return to the default position.

Referring to FIG. 6B, which shows the leg/knee support 50 in a second extreme tilted position where the outer casing 500 is pivoted in the counter-clockwise direction about pivot axis PA3, pivotal movement of the outer casing 500 conversely causes an extension of the first (upper) spring element 511 compared to the default position illustrated in FIG. 5. By contrast, the second (lower) spring element 512 is relieved from any tension in this case. In this second extreme tilted position the second (lower) spring mount 502 comes in abutment with a corresponding section of the retaining device 51, preventing further pivotal movement of the outer casing 500 in the counter-clockwise direction. When the external force applied on the outer casing 500 is suppressed (namely when the contact with the patient's legs or knees is interrupted), the first spring element 511 will likewise automatically pull the outer casing 500 to pivot in the clockwise direction and return to the default position.

One may thus appreciate that, in accordance with this embodiment of the invention, each spring mount 501, 502 further acts as stop element limiting pivotal movement of the outer casing 500 about the pivot axis PA3. Advantageously, the leg/knee support 50 is configured so that a total amplitude of pivoting movement thereof with respect to the support mount 120 is of the order of 10 to 30 degrees. For the sake of illustration, the leg/knee support 50 shown in FIGS. 5 and 6A-B is here configured to have a pivoting range of the order of +/−8 degrees about de default position, i.e. a total amplitude of pivoting movement of the order of 16 degrees.

The aforementioned solution allowing pivotal movement of the outer casing 500 with respect to the retaining device 51 is of great advantage to improve comfort for the patient during transfer from a seated position to a standing position, and vice versa, as the outer casing 500 will follow the actual and natural movement of the patient's legs and knees during the assisted transfer. The proposed solution is fully integrated and is not made to detriment of the operation of the aforementioned manually-operable release mechanism. In other words, both functions can be implemented, without this leading to a complex arrangement.

Various modifications and/or improvements may be made to the above-described embodiments without departing from the scope of the invention as defined by the annexed claims.

LIST OF REFERENCE NUMERALS AND SIGNS USED THEREIN

-   1 patient lift apparatus/stand-assist hoist -   10 supporting frame -   11 base member -   12 mast -   12A mast extension for connection of leg/knee support 50 -   13 supporting legs -   14 casters -   15 boom actuator -   15A end of boom actuator 15 connected to mounting bracket 185 -   16 steering handle -   18 boom portion pivotably connected to supporting frame 10 -   20 handle portions provided on boom portion 18 for manual grip -   25 hook portions provided on boom portion 18 for attachment of a     sling (not shown) -   50 (padded) leg/knee support (or “leg/knee pad”) connected to     supporting frame 10 via mast extension 12A and support mount     120/configured to be selectively releasable from supporting frame 10     and to be partly pivotable with respect to supporting frame 10 -   51 retaining device 51 configured to cooperate with support mount     120 to secure leg/knee support 50 onto supporting frame 10     (component of manually-operable release mechanism 51/52/55) -   51A (first) retaining member of retaining device 51 -   51B (second) retaining member of retaining device 51 -   52 cable coupling manually-operable handle 55 to retaining device 51     (component of manually-operable release mechanism 51/52/55) -   52A guide elements for cable 52 -   55 manually-operable (e.g. sliding) handle cooperating with     retaining device 51 to allow selective release of retaining device     51 from support mount 120 (component of manually-operable release     mechanism 51/52/55) -   60 foot support (or “foot plate”) connected to supporting frame 10     via base member 11 -   120 support mount provided on supporting frame 10 at an end of mast     extension 12A -   120A positioning holes distributed along portion of support mount     120 -   180 telescopic arm 180 of boom portion 18 -   181 outer member of telescopic arm 180 -   181A inner side of outer member 181 -   182 inner member of telescopic arm 180 telescopically received     inside outer member 181 -   182A positioning holes distributed longitudinally along portion of     inner member 182 -   182B outer periphery of inner member 182 -   185 mounting bracket located on lower portion of outer member 181     and supporting manually-operable release lever 250 -   200 indexing mechanism configured to allow positioning of inner     member 182 at a plurality of predefined longitudinal positions with     respect to outer member 181 -   210 releasable (e.g. spring-loaded) indexing plunger of indexing     mechanism 200/mounted on outer member 181 -   210A retractable end portion of releasable indexing plunger 210     configured to engage with selected positioning hole 182A -   250 manually-operable release lever of indexing mechanism     200/mechanically linked to releasable indexing plunger 210 -   250A end of manually-operable release lever 250 coupled to     releasable indexing plunger 210 -   250B pivot of manually-operable release lever 250 -   280 cover element located on bracket 185 covering part of indexing     mechanism 200 and preventing finger or hand entrapment -   300 centering system designed to suppress clearance between outer     member 181 and inner member 182 -   310 (first) centering element of centering system 300 mounted on     outer member 181/(spring-loaded) bushing member mounted on distal     end portion of outer member 181 and interposed between inner side     181A of outer member 181 and outer periphery 182B of inner member     182 -   310A extensions on bushing member 310 for mounting flat spring     elements 315 -   310B extensions on bushing member 310 for attachment to distal end     portion of outer member 181 -   315 flat spring elements mounted on extensions 310A and designed to     press against inner side 181A of outer member 181 and press     extensions 310A inwardly towards outer periphery 182B of inner     member 182 -   320 (second) centering element of centering system 300 mounted on     inner member 182/guide member mounted on distal end portion of inner     member 182 and guided inside the outer member 181 -   320A guide surfaces on outer periphery of guide member 320 for -   guidance against inner side 181A of outer member 181 -   500 outer casing of leg/knee support 50 -   500A support surfaces on outer casing 500 for supporting patient's     legs/knees -   501 (first) spring mount on outer casing 500 for (first) spring     element 511/(first) stop element) -   502 (second) spring mount on outer casing 500 for (second) spring     element 512/(second) stop element -   510 releasable (e.g. spring-loaded) indexing plunger of retaining     device 51 -   510A retractable end portion of releasable indexing plunger 510     configured to engage with selected positioning hole 120A -   511 (first) spring element (e.g. tension spring) coupling outer     casing 500 to retaining device 51/configured to bring outer casing     500 to default position with respect to retaining device 51 -   512 (second) spring element (e.g. tension spring) coupling outer     casing 500 to retaining device 51/configured to bring outer casing     500 to default position with respect to retaining device 51 -   PA1 pivot axis of boom portion 18 with respect to mast 12 (parallel     to y-axis) -   PA2 pivot axis of manually-operable release lever 250 with respect     to mounting bracket 185 -   PA3 pivot axis of outer casing 500 with respect to retaining device     51 -   PJ1 pivot joint between boom portion 18 and mast 12 

1-17. (canceled)
 18. A patient lift apparatus comprising a supporting frame, a boom portion connected to the supporting frame via a pivot joint to allow the boom portion to pivot with respect to the supporting frame about a pivot axis, and a boom actuator to mechanically assist pivotal movement of the boom portion with respect to the supporting frame, wherein the boom portion is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member and adjustment of an effective length of the telescopic arm, wherein the patient lift apparatus further comprises a centering system configured to center the inner member with respect to the outer member and suppress a clearance between the inner member and outer member, wherein the centering system includes: a first centering element mounted on the outer member and interposed between an inner side of the outer member and an outer periphery of the inner member; and a second centering element mounted on the inner member and guided inside the outer member, wherein the first and second centering elements are configured to suppress the clearance between the outer member and inner member, wherein the first centering element is configured as a bushing member mounted on a distal end portion of the outer member, a portion of which bushing member extends between the inner side of the outer member and the outer periphery of the inner member, and wherein the second centering element is configured as a guiding member mounted on a distal end portion of the inner member and guided inside the outer member.
 19. The patient lift apparatus according to claim 18, wherein the bushing member comprises a plurality of extensions extending longitudinally between the inner side of the outer member and the outer periphery of the inner member and a plurality of flat spring elements located on said extensions.
 20. The patient lift apparatus according to claim 19, wherein the flat spring elements are interposed between the inner side of the outer member and said extensions to press the said extensions inwardly towards the outer periphery of the inner member.
 21. The patient lift apparatus according to claim 18, further comprising an indexing mechanism configured to allow positioning of the inner member at a plurality of predefined longitudinal positions with respect to the outer member.
 22. The patient lift apparatus according to claim 21, wherein the indexing mechanism comprises a releasable indexing plunger mounted on the outer member and having a retractable end portion configured to engage with any selected positioning hole among a plurality of positioning holes distributed longitudinally along a portion of the inner member.
 23. The patient lift apparatus according to claim 22, wherein the centering system is mounted on the outer member and inner member and configured such as not to interfere with operation of the releasable indexing plunger.
 24. The patient lift apparatus according to claim 22, wherein the indexing mechanism further comprises a manually-operable release lever that is mechanically linked to the releasable indexing plunger to selectively allow retraction of the retractable end portion of the indexing plunger out of engagement with the selected positioning hole, thereby releasing the inner member and allowing repositioning of the inner member with respect to the outer member at a different one of the predefined longitudinal positions.
 25. The patient lift apparatus according to claim 24, wherein one end of the manually-operable release lever is coupled to the releasable indexing plunger and wherein an intermediate portion of the manually-operable release lever is configured to act as a pivot about which the manually-operable release lever can pivot upon being manually operated to cause retraction of the retractable end portion of the indexing plunger.
 26. The patient lift apparatus according to claim 24, wherein the indexing mechanism is located on a lower portion of the outer member, and wherein the manually-operable release lever is supported onto a same mounting bracket as one end of the boom actuator.
 27. The patient lift apparatus according to claim 26, wherein a cover element is located on said mounting bracket, covering part of the indexing mechanism, to prevent finger or hand entrapment.
 28. The patient lift apparatus according to claim 21, wherein the indexing mechanism is located on a lower portion of the outer member.
 29. The patient lift apparatus according to 22, wherein the releasable indexing plunger is a spring-loaded indexing plunger whose retractable end portion is configured to be urged towards an inner side of the outer member and to automatically engage with any one of the plurality of positioning holes provided on the inner member upon alignment therewith.
 30. The patient lift apparatus according to claim 18, further comprising a leg/knee support connected to the supporting frame.
 31. The patient lift apparatus according to claim 30, wherein the leg/knee support is configured to be selectively releasable from the supporting frame.
 32. The patient lift apparatus according to claim 31, wherein the leg/knee support comprises a manually-operable release mechanism to selectively release the leg/knee support from the supporting frame.
 33. The patient lift apparatus according to claim 30, wherein the leg/knee support is configured to be partly pivotable with respect to the supporting frame about an axis of rotation and within a defined pivoting range.
 34. A patient lift apparatus comprising a supporting frame, a boom portion connected to the supporting frame via a pivot joint to allow the boom portion to pivot with respect to the supporting frame about a pivot axis, and a boom actuator to mechanically assist pivotal movement of the boom portion with respect to the supporting frame, wherein the boom portion is configured as a telescopic arm comprising an outer member and an inner member that is telescopically received inside the outer member to allow displacement of the inner member with respect to the outer member and adjustment of an effective length of the telescopic arm, wherein the patient lift apparatus further comprises an indexing mechanism configured to allow positioning of the inner member at a plurality of predefined longitudinal positions with respect to the outer member, wherein the indexing mechanism comprises a releasable indexing plunger mounted on the outer member and having a retractable end portion configured to engage with any selected positioning hole among a plurality of positioning holes distributed longitudinally along a portion of the inner member, wherein the indexing mechanism further comprises a manually-operable release lever that is mechanically linked to the releasable indexing plunger to selectively allow retraction of the retractable end portion of the indexing plunger out of engagement with the selected positioning hole, thereby releasing the inner member and allowing repositioning of the inner member with respect to the outer member at a different one of the predefined longitudinal positions, wherein one end of the manually-operable release lever is coupled to the releasable indexing plunger and wherein an intermediate portion of the manually-operable release lever is configured to act as a pivot about which the manually-operable release lever can pivot upon being manually operated to cause retraction of the retractable end portion of the indexing plunger.
 35. The patient lift apparatus according to claim 34, wherein the indexing mechanism is located on a lower portion of the outer member, and wherein the manually-operable release lever is supported onto a same mounting bracket as one end of the boom actuator.
 36. The patient lift apparatus according to claim 35, wherein a cover element is located on said mounting bracket, covering part of the indexing mechanism, to prevent finger or hand entrapment.
 37. The patient lift apparatus according to claim 34, wherein the indexing mechanism is located on a lower portion of the outer member.
 38. The patient lift apparatus according to claim 34, wherein the releasable indexing plunger is a spring-loaded indexing plunger whose retractable end portion is configured to be urged towards an inner side of the outer member and to automatically engage with any one of the plurality of positioning holes provided on the inner member upon alignment therewith.
 39. The patient lift apparatus according to claim 34, further comprising a leg/knee support connected to the supporting frame.
 40. The patient lift apparatus according to claim 39, wherein the leg/knee support is configured to be selectively releasable from the supporting frame.
 41. The patient lift apparatus according to claim 40, wherein the leg/knee support comprises a manually-operable release mechanism to selectively release the leg/knee support from the supporting frame.
 42. The patient lift apparatus according to claim 39, wherein the leg/knee support is configured to be partly pivotable with respect to the supporting frame about an axis of rotation and within a defined pivoting range. 